Dominance status in female ring-tailed lemurs (Lemur catta) has a pervasive effect upon social organization, however the proximate mechanisms underlying female rank-relations remain poorly understood. I investigated how four such attributes - weight, age, agonistic frequency, and fecal testosterone levels - relate to female rank-order wild ring-tailed lemurs at the Beza Mahafaly Special Reserve, Madagascar. My results indicated that: (1) The mean weight of high-ranking females is significantly greater than in lower-ranking females; (2) The relationship of age in relation to rank follows an inverted J-shaped pattern, with old adults attaining the highest average rank, followed by prime adults, young adults, and very old adults; (3) Significant, positive correlations between rank and rates of agonism exist in four of the six study groups; and (4) The effect of rank on mean testosterone concentration was significant in one social troop, in which the two highest ianking females exhibited significantly lower mean testosterone levels.

Lemur fulvus, the brown lemur, is a cat-sized arboreal prosimian, native to Madagascar and the island of Mayotte, in the Comoro Archipelago. A social prosimian, ~ fulvus typically forms cohesive troops of from 5-15 individuals. Troop composition is usually reported to be at, or near, a 1:1 sex ratio. The problems examined in this thesis were chosen in order to address aspects of L. fulvus social dynamics that are unclear, given the depiction of L. fulvus social behaviour presented in the primate literature. What are adult males doing, in the reported absence of agonistically-determined dominance hierarchies, to gain and maintain access to estrus females? Given the breeding season behavioural changes and fluctuations exhibited by adult males (a behavioural complex here termed, "fall-fever"), how do these changes and fluctuations contribute to male L. fulvus breeding opportunities, and potential reproductive success? These questions were investigated in the study of a semi-free-ranging ~ fulvus troop during the 1984 (Northern Hemisphere) breeding season. Utilizing an extensive ethogram it was found that, contrary to previous literature on the species, hierarchical social dominance relationships are indeed present in L. fulvus social groups. Additionally, it was found that these relationships play a crucial role in the reproductive behaviour of adult males. Statistically significant variation in the behaviour of the focal males is presented for seven inclusive behavioural categories. The picture of male L. fulvus reproductive behaviour that emerges from these considerations is then compared to the view derived from previous research on the species. Several amendments to our understanding of ~ fulvus social behaviour are suggested. An attempt is also made to place ~ fulvus in the socioecological categorizations of several authors. / Thesis / Master of Arts (MA)

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Sex-specific calls are used in male-male agonistic encounters and male-female courtship in many animal species. The ring-tailed lemur (Lemur catta) is a gregarious Malagasy strepsirhine with twenty-two distinct vocalizations for adults, including two male-specific vocalizations and an additional vocalization with male-specific functions: the howl, the squeal, and the purr. Proposed intra-sexual agonistic functions for these three vocalizations have never been empirically tested. This study’s purpose was to investigate the functions of howling, squealing, and purring in the ring-tailed lemur, and to assess the relationships between the rates of these vocalizations and male dominance. From March to July 2010, I collected 600 hours of total data and 480 hours of focal data on male ring-tailed lemurs aged three and older at Beza Mahafaly Special Reserve, Madagascar. I observed each male continuously for 30 minutes at a time and noted behaviours including all vocalizations and all agonism using one–zero sampling at 2.5-min intervals. I calculated male dominance rank and vocalization rates from these data. My results indicated that male dominance rank is correlated with male purring rate and with squealing rate, but not with howling rate. Male purring rate increased during intra-sexual agonism and was associated with aggression in agonistic encounters. Squealing rate increased during male-male agonism and indicated both aggression and submission in male-male encounters. Howling rate increased during inter-group encounters and a greater number of males participated in multi-male howling choruses when non-group members were present. Purring and squealing are agonistic vocalizations and used in male-male agonism in the ring-tailed lemur, while howling is used in inter-group encounters.

Sex-specific calls are used in male-male agonistic encounters and male-female courtship in many animal species. The ring-tailed lemur (Lemur catta) is a gregarious Malagasy strepsirhine with twenty-two distinct vocalizations for adults, including two male-specific vocalizations and an additional vocalization with male-specific functions: the howl, the squeal, and the purr. Proposed intra-sexual agonistic functions for these three vocalizations have never been empirically tested. This study’s purpose was to investigate the functions of howling, squealing, and purring in the ring-tailed lemur, and to assess the relationships between the rates of these vocalizations and male dominance. From March to July 2010, I collected 600 hours of total data and 480 hours of focal data on male ring-tailed lemurs aged three and older at Beza Mahafaly Special Reserve, Madagascar. I observed each male continuously for 30 minutes at a time and noted behaviours including all vocalizations and all agonism using one–zero sampling at 2.5-min intervals. I calculated male dominance rank and vocalization rates from these data. My results indicated that male dominance rank is correlated with male purring rate and with squealing rate, but not with howling rate. Male purring rate increased during intra-sexual agonism and was associated with aggression in agonistic encounters. Squealing rate increased during male-male agonism and indicated both aggression and submission in male-male encounters. Howling rate increased during inter-group encounters and a greater number of males participated in multi-male howling choruses when non-group members were present. Purring and squealing are agonistic vocalizations and used in male-male agonism in the ring-tailed lemur, while howling is used in inter-group encounters.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Ring-tailed lemur Lemur catta, red ruffed lemur Varecia rubra and black and white ruffed lemur Varecia variegata belongs to the family Lemuridae, living at Madagaskar as endemits. In wildlife is folivorous and frugivorous food strategy at the both genus ? in the process g. Varecia is more frugivorous. Study was divided into two parts ? the first about ration of feeding chosen species of lemurs in several czech zoos and the second about ethology feeding behaviour lemurs in zoo Jihlava. For nutritional assessment were further chosen zoos Lešná, Jihlava, Ústí nad Labem, Ohrada and Chleby. From ration of feeding for chosen species of lemurs was counted average personal ration per day. This average was used to calculate nutritional values of dietary (fats, protein, carbohydrates, fiber, calcium, phosporus and iron) for each kind of menu or particularly day a week. For ethologic observation was made method of straight observation with used behaviour sampling ? scanning of a behaviour. Observation was done from July to December 2011 in whole extent 56 hours. Study solved out that ration of feeding are very different in each zoo like nutritional values of dietary and amount. In each zoo has larger ration of feeding Varecia rubra than Lemur catta. In average this diference beetwen that makes 144,25 g. Observation (zoo Jihlava) showed that Lemur catta spends foraging behaviour 19,75 minutes per day and handling 42,75 minutes per day in average. All in all they spending their feeding behavior only 62,5 minutes (1,04 hours) per day. Further more was discovered diference in length feeding behaviour when in their habitation more tree branches were. Adding branches to there increased length of feeding behaviour about of 22,67 minutes per day.

Global climate change and habitat fragmentation represent two of the greatest threats to biodiversity and ecological processes worldwide. It is predicted that anthropogenic induced climate change could represent a key factor for extinctions in the near future, considering that the Earth is set to become warmer than at any period in the past 40 million years. Habitat fragmentation and isolation pose a number of challenges for the fauna inhabiting degraded areas, including lack of dispersal opportunities leading to inbreeding resulting in a loss of genetic diversity, reduced reproductive fitness; increases in vulnerability to predation, hunting, and disease, and an inability to deal with or respond to environmental changes and/or disease. Madagascar, the fourth largest island in the world, is home to unprecedented levels of endemism, including over 100 species of lemur. The island has undergone a range of historical and contemporary landscape transformations, both natural and anthropogenic. These landscape transformations combined with additional human-induced disturbances, such as the illegal pet and bushmeat trades, have had devastating effects on the island’s extant primate populations. Thus, Madagascar’s lemurs have been deemed the most endangered group of mammals and now represent the highest primate conservation priority in the world. The ring-tailed lemur (Lemur catta) is endemic to the southern regions of the island and occupies an array of habitats. L. catta is known for its remarkable behavioral and ecological flexibility, which contributes to its ability to exist in a mostly fragmented landscape. While this species represents one of the most well studied Malagasy strepsirhines, there has been a paucity of research regarding the population and conservation genetics of this endangered species. The goal of my dissertation was to examine the influence of habitat fragmentation and isolation on the genetic diversity and population structuring of this flagship species in three populations living in the central highlands of Madagascar: Anja Reserve, Sakaviro, and Tsaranoro Valley. Non-invasive fecal samples from 30 individual lemurs were collected from three fragmented forests and genotyped at six polymorphic microsatellite loci. Population genetic analyses were examined via GenAlEx software and revealed a moderate level genetic diversity. Genetic differentiation (FST) among the three fragmented populations ranged from 0.05-0.11. These data suggest that the L. catta populations within south-central Madagascar have not yet lost significant genetic variation. To examine past and recent demographic declines or genetic bottlenecks, I employed three approaches, including mode-shift and M-Ratio tests, as well as a test to detect heterozygosity excess using three mutation models: the two-phase model (TPM), step-wise mutation model (SMM), and the infinite allele model (IAM). Results were equivocal depending on the test that was applied; however, a mode-shift was detected for Anja, signifying this population underwent a historical bottleneck. M-ratio tests revealed that all three populations suffered historical bottlenecks. A population bottleneck was indicated via heterozygosity excess under the IAM for both the Anja and Sakaviro populations. To understand the impact of natural (e.g., mountains) and anthropogenic disturbances (e.g., roads, habitat fragmentation) on male reproductive strategies (dispersal) and population structuring, I utilized both GenAlEx and STRUCTURE software. Population assignment analyses suffered from a likely ‘lack of signal’. Therefore, individuals were unable to be reliably assigned to their population of origin. Genetic population structure was ambiguous. These data suggest that that these three fragmented populations are not genetically differentiated enough for proper population assignment, or perhaps the sample is not robust enough for population assignment analyses to produce unequivocal results. My research represents the first population genetic data for ring-tailed lemurs within the central highlands, and thus, serves as a baseline for future investigations into the genetic health of these populations. These data support the suggestion that these three fragments represent areas in which concerted conservation efforts are necessary if genetic diversity is to be maintained and future demographic declines are to be prevented. My results are informative for the local community conservation associations working within south-central Madagascar and can now be applied to determine areas of conservation priority and where forest corridors will be the most beneficial for maintaining gene flow. The loss and fragmentation of habitat continues across Madagascar, including the central highlands; thus, all remaining L. catta populations should be considered a high conservation priority. If we are to safeguard the long-term viability of this species, continued conservation and research initiatives will be crucial. / Graduate / 0327 / 0369 / lemurgirl.clarke@gmail.com

<p>There is a long-standing claim that humans and nonhuman primates share an evolutionarily ancient system of nonverbal number representation. By and large, the focus in the field has been on providing existence proofs of numerical competence in wide-ranging taxa or using individual species as models for comparisons with humans. Recent findings in numerical cognition have suggested that evidence for approximate numerical abilities in nonhuman species may indicate that humans and animals share a cognitive system for representing numerosities nonverbally. To date, little is known about the contextual and quantitative limits of that system, or how those limits differ between species. The studies presented here take a comparative, behavioral approach to characterizing species differences and similarities in the approximate number system, and the contexts that affect that system. Collectively, this set of studies provides evidence that the approximate number system evolved in primates as a malleable system in which numerical representations are accessed spontaneously and improved through training. Despite the sensitivity of the system to experience and context individual differences in sensitivity are greater than species differences suggesting that the selective pressures that constrained its evolution were early and general and that species variation in social group size and diet have less influence on the ANS. Finally my studies indicate that the ANS supports approximate arithmetic and is consistent with the idea that ANS representations evolved to allow animals to calculate the world around them.</p> / Dissertation

Primate habitats differ dramatically in the intensity and spectral quality (color) of ambient light. However, little research has explored the effects of habitat variation in ambient light on primate and mammalian visual systems. An understanding of variation in nocturnal light environments is particularly lacking, considering the significance of nocturnality and vision in primate evolutionary hypotheses. In this dissertation, I explored effects of habitat variation in light environments on primate visual evolution in three studies. First, I examined how variation in ambient light intensity influenced visual morphology in 209 mammals. Second, I analyzed effects of variation in nocturnal light environments on color vision in nocturnal primates and mammals. For this second objective, I first identified factors influencing variation in nocturnal light environments within and between habitats in Madagascar and explored how nocturnal light spectral quality has influenced mammalian visual pigment spectral tuning. I then analyzed selection acting on the SWS1 opsin gene (coding for blue-sensitive cone visual pigments) between nocturnal lemurs from different habitat types to explore whether nocturnal light environments affect selection for dichromatic color vision. The results of all three studies suggest that habitat variation in light environments has had a significant influence on primate and mammalian visual evolution. In the first study, I found that day-active mammals from forested habitats exhibited larger relative cornea size compared to species from open habitats, reflecting an adaptation to increase visual sensitivity in diurnal forests. The results of the second study revealed that forest and woodland habitats share a yellow-green dominant nocturnal light environment and that nocturnal vertebrates exhibit visual pigments tuned to maximize photon absorption in these environments. Additionally, I observed a potential effect of diet on long-wavelength-sensitive cone spectral tuning among nocturnal mammals. In the third study I sequenced the SWS1 opsin gene in 106 nocturnal lemurs (19 species). Both population genetic and phylogenetic analyses identified clear signatures of differential selection on the gene by habitat type, suggesting that nocturnal light environments has influenced selection for nocturnal dichromacy in nocturnal lemurs. Finally, I discussed the implications of these results for nocturnal primate visual ecology and evolution. / text